The above-referenced patent application pertains to so-called downhole, spiral or stationary auger type separator devices, primarily adapted for separating gas from liquid being produced from a hydrocarbon fluid production well. In certain wells which produce hydrocarbon fluids, for example, both gas and liquids are produced simultaneously directly from one or more production zones. Gas and liquid may also be produced simultaneously from wells which utilize artificial gas lift or which are producing oil which has been driven to the production well by pressurized gas injection into the subterranean reservoir. Accordingly, elaborate and expensive separation and treatment facilities are usually required to separate gas from production liquids. In some instances, it is also desirable to separate more dense gasses or liquids from less dense gasses or liquids in wells which are producing various types of hydrocarbon fluids, such as both water and crude oil, for example.
As well operating conditions change with respect to the relative amounts of oil and gas being produced, or the relative amounts of oil, water and gas, it is often necessary to modify the separator facilities. Still further, changing proportions of oil, water and gas, for example, can cause slug flow in the fluid production flowlines, and can put undue loading on all or portions of the existing separator facilities. Moreover, if the separated gas is to be used for reservoir injection or for artificial gas lift in other wells, the remote location of conventional separator facilities usually requires extensive piping to return the gas to the injection wells or the wells using gas lift.
Downhole separation of gas from liquids can provide a high pressure gas source for gas lift and for compression by nearby disposed compressors for reinjection. Downhole separation will usually also provide higher pressure gas at the surface due to reduced pressure losses in the flow conduits. However, insertion of and retrieval of a downhole separator, such as the types described in the above-mentioned patent application can be somewhat difficult and expensive to accomplish. Moreover, changing flow conditions may dictate a change in the separator position, size or other design features, and premature wear due to abrasives in the fluid flowstream may also require repair or replacement of the separator. Accordingly, a downhole location of the separator can require expensive and time consuming operations to replace or repair the separator itself.
On the other hand, surface installation of an inline spiral or so-called auger type separator may be easily accomplished by inserting the separator structure in a conventional flowline with minimal interruption of well operations and with minimal expense with regard to equipment costs. Existing valving and controls may be utilized to a large extent in the flowlines, and no expensive installation procedures or structures are required, such as support pads, buildings or other enclosures usually necessary for conventional separator systems. Still further, surface disposed inline type separators may be arranged in multistage configurations to obtain substantial gas-liquid separation, separation of gasses and/or liquids of different densities from each other and/or separation of particulate solids from gas and/or liquids. Separation of gas at the surface and adjacent to the fluid production well may also minimize piping requirements if the separated gas is required for reservoir injection or artificial gas lift. Certain processes may also favor separation of water from oil and transport of these liquids in separate conduits to minimize corrosion problems. For example, it may be advantageous to separate water or brine from produced oil and conduct these fluids in separate flowlines to a process facility and wherein certain corrosion inhibitors may be injected into the oil or water flowlines to minimize corrosion. Such arrangements would be beneficial wherein, for example, the corrosion inhibitors would not be suitable for mixing with one or the other of the fluids due to its process requirements. Still further, a mechanically simple, low cost separator which is at least capable of partial gas-liquid separation or partial separation of fluids of different densities is desirable and is particularly useful for separating produced fluids in many hydrocarbon production well operations and in other fluid process applications.